How to convert “double” to “datetime” between Excel and c#

Question

I have a c# program which needs to create an excel object, and do some operations, here are parts of my code:

// c# code:

workSheet.Cells[1, 1] = \"=2012/9/20\         


        

Answer 1

By typing is `=2012/9/20" you're telling Excel that this is a formula. 2012 divided by 9, divided by 20 equal 11.17777777778.

Try storing the date without the = sign.